P2374 – Knock Sensor 1 Circuit Intermittent (Bank 1)

System: Powertrain | Standard: ISO/SAE Controlled | Fault type: Circuit Intermittent | Location: Bank 1, Sensor 1

Definition source: SAE J2012/J2012DA (industry standard)

P2374 indicates the powertrain controller has detected an intermittent condition in the Knock Sensor 1 circuit on Bank 1. “Intermittent” points to a signal or circuit integrity issue that comes and goes rather than a constant high, low, or open circuit. Because knock sensor design, wiring routes, shielding, and monitor logic vary by vehicle, the exact enable conditions and detection strategy can differ. Use service information for your specific vehicle to confirm connector pinouts, harness routing, and test specifications before making repairs. Do not assume a sensor is faulty without circuit testing.

What Does P2374 Mean?

P2374 – Knock Sensor 1 Circuit Intermittent (Bank 1) means the control module is seeing an inconsistent or unstable electrical condition in the Knock Sensor 1 circuit for Bank 1. Under SAE J2012 DTC conventions, this type of code describes the observed fault behavior (intermittent circuit behavior) rather than confirming a failed component. The issue may be caused by wiring or connector problems, poor terminal contact, intermittent power/ground/reference integrity (varies by vehicle), or a knock sensor whose internal connection becomes unstable under vibration or heat. Diagnosis should focus on reproducing and capturing the intermittent event.

Quick Reference

• System: Powertrain
• Official meaning: Knock Sensor 1 Circuit Intermittent (Bank 1)
• Standard: ISO/SAE controlled
• Fault type: Circuit Intermittent
• Severity: MIL illumination is possible; engine performance may be affected if knock control is limited or erratic, which can lead to reduced power or drivability complaints.

Symptoms

• MIL/Check engine: Malfunction indicator lamp may illuminate, sometimes after an intermittent event is detected more than once.
• Intermittent drivability: Occasional hesitation, surging, or unstable acceleration that may come and go with vibration, bumps, or heat soak.
• Reduced power: Power may feel limited if the control module applies protective ignition strategy when knock feedback is unreliable.
• Poor fuel economy: Fuel consumption can increase if ignition timing is adjusted conservatively due to inconsistent knock feedback.
• Roughness under load: Light stumble or roughness during heavy throttle or climbing may occur intermittently.
• Inconsistent timing behavior: Live data (if available) may show knock-related parameters fluctuating unexpectedly during the fault.

Common Causes

• Intermittent wiring open: Broken conductor or internal wire damage in the knock sensor signal circuit that makes contact only sometimes.
• Poor connector contact: Loose terminal fit, fretting/corrosion, bent pins, or partially backed-out terminals at the sensor or control module connector.
• Harness routing/strain: Wiring rubbed through, pinched, stretched, or contacting hot/moving parts causing momentary opens/shorts as the engine moves.
• Ground integrity issue: Shared ground splice or ground path with intermittent resistance changes (varies by vehicle design).
• Signal contamination: Intermittent short between signal and another circuit due to insulation damage or moisture intrusion in a connector.
• Knock sensor internal intermittency: Sensor element or internal connection intermittently failing under heat, vibration, or torque changes.
• Engine mechanical noise/vibration interaction: Abnormal vibration that intermittently disturbs the sensor or harness connection (verify mechanically only after circuit checks).
• Control module/terminal issue: Rare terminal tension problem at the control module connector or an internal fault that presents as an intermittent circuit condition.

Diagnosis Steps

Tools helpful for diagnosing an intermittent knock sensor circuit include a scan tool with live data and data-logging, a digital multimeter, and basic back-probing tools. Access to service information is important for connector views, pin IDs, and the correct circuit description (power/ground/shielding varies by vehicle). A wiring inspection light, terminal inspection tools, and supplies for connector cleaning/repair are also useful.

1. Confirm the code and capture context: Use a scan tool to confirm P2374 is present and record freeze-frame data and any related DTCs. Note engine speed/load and coolant temperature when the fault set, since intermittents often correlate to vibration, heat soak, or specific RPM ranges.
2. Check for related electrical faults first: If other power, ground, reference, or sensor-circuit DTCs are present, diagnose those first. Intermittent shared power/ground issues can cascade into intermittent sensor-circuit codes.
3. Verify the correct component and location: Using service information, identify “Knock Sensor 1 (Bank 1)” and the exact connector/circuit pins involved. Do not assume sensor numbering or bank assignment; it varies by vehicle.
4. Perform a focused visual inspection: Inspect the sensor connector, harness routing, and nearby clamps/retainers. Look for chafing, pinched wiring, oil/coolant contamination, moisture intrusion, prior repairs, and contact with hot or moving components.
5. Connector and terminal checks: With ignition off, disconnect the sensor connector and inspect for bent pins, corrosion, spread terminals, or partial terminal push-out. Check terminal tension/fit (as applicable) and ensure connectors fully lock when reinstalled.
6. Wiggle test with live-data logging: Reconnect and monitor the knock sensor parameter(s) on the scan tool while gently wiggling the harness at key points (sensor pigtail, bends, clips, splices, and near the control module). Log data and watch for dropouts, spikes, or a status change that coincides with movement.
7. Check circuit continuity for intermittents: With the circuit safely isolated per service information, test continuity from the sensor connector to the control module connector. While measuring, flex the harness and lightly tap connectors to try to reproduce an open. If the meter reading changes with movement, locate the exact section causing the interruption.
8. Inspect for intermittent shorts/contamination: Test for unintended continuity between the knock sensor signal circuit and ground or other circuits (per the wiring diagram). Manipulate the harness during testing to reveal intermittent contact caused by insulation damage or moisture in connectors.
9. Voltage-drop test the ground path (if applicable): If the sensor uses a defined ground circuit (varies by vehicle), perform voltage-drop testing on the ground path while the circuit is operating. Repeat under conditions that reproduce the fault (heat, vibration, higher RPM) and compare to service-information guidance.
10. Assess sensor behavior only after circuit integrity is proven: If wiring/connector checks are good yet the fault persists, evaluate the sensor for intermittent operation per service procedures (for example, monitoring response changes with heat soak or vibration). Replace the sensor only when testing supports an intermittent internal fault.
11. Verify the repair: After repairs, clear codes and perform a road test while data-logging knock sensor parameters. Include conditions similar to the freeze-frame and recheck for pending codes to confirm the intermittent issue is resolved.

Professional tip: Intermittent circuit faults are often caused by terminal tension or a conductor broken inside intact insulation. If the code appears after bumps, heat soak, or specific RPM ranges, prioritize a methodical wiggle test with data logging and connector/terminal inspection before replacing parts; reproduce the fault first, then repair what you can prove.

Possible Fixes & Repair Costs

Repair costs for P2374 vary widely because the root cause can be an intermittent wiring/connector issue, a sensor problem, or a module-side concern. Total cost depends on the time required to reproduce the fault, confirm it with testing, and access the sensor and harness for repair.

• Repair wiring damage: Repair or replace chafed, pinched, stretched, or heat-damaged wiring in the Knock Sensor 1 circuit on Bank 1 after confirming the intermittent opens/shorts with testing.
• Connector service: Clean and dry connectors, correct terminal tension/fit issues, and repair broken locks or seals if movement or vibration triggers the intermittent fault.
• Secure routing and retention: Re-route and properly clip the harness to reduce vibration-induced intermittents; add protective loom or abrasion protection where needed.
• Address poor grounds or power feeds: Restore grounds/power feeds shared with the circuit if voltage-drop testing confirms intermittent supply/return problems (varies by vehicle design).
• Replace Knock Sensor 1 (Bank 1): Replace the sensor only after confirming the circuit is intact and the intermittent follows the sensor or its connection rather than the harness.
• Repair related connector/pigtail: Replace a damaged pigtail/connector body if terminal repairs are not reliable or if water intrusion/strain damage is present.
• Module-side repair (rare): If all external circuit testing is conclusive and the fault is repeatable at the module connector, follow service information for module pin checks and repair/replace only as directed.

Can I Still Drive With P2374?

You can often drive short distances with P2374, but proceed cautiously because an intermittent Knock Sensor 1 circuit signal on Bank 1 can affect how the powertrain control system manages ignition timing and engine load protection. If you notice reduced power, severe pinging/knock sounds, misfires, overheating, stalling, or any warning messages that indicate limited operation, avoid driving and have the vehicle diagnosed to prevent possible engine damage.

What Happens If You Ignore P2374?

Ignoring P2374 may lead to recurring warning lights, intermittent drivability complaints, and inconsistent engine performance because the fault can appear and disappear with vibration, temperature changes, or harness movement. Over time, the underlying intermittent wiring/connector problem can worsen, potentially causing additional circuit faults or more pronounced performance issues.

Last updated: February 15, 2026

Vehicles Commonly Affected by P2374

• Vehicles with V-type engines: Bank 1 identification and sensor placement can increase exposure to heat and vibration depending on layout.
• High-mileage vehicles: Aging insulation, brittle loom, and terminal fretting can create intermittent circuit contact.
• Vehicles with tight engine bays: Harnesses routed near hot components or sharp edges are more prone to chafing and intermittent opens/shorts.
• Vehicles exposed to moisture: Water intrusion or corrosion at connectors can cause intermittent signal interruption.
• Vehicles with prior engine work: Harness strain, misrouting, or partially seated connectors after repairs can trigger intermittent circuit faults.
• Vehicles operated on rough roads: Vibration can aggravate weak terminal contact or broken conductors inside insulation.
• Vehicles with rodent damage history: Partially damaged conductors may pass continuity tests yet fail intermittently under load or movement.
• Vehicles with oil/coolant contamination: Fluid intrusion into connectors or loom can degrade terminals and create unstable electrical contact.

Always verify the repair by confirming stable knock sensor circuit behavior during a drive cycle and by rechecking for pending or stored diagnostic trouble codes after the conditions that previously triggered P2374.